diff options
| -rw-r--r-- | src/corelib/tools/qregularexpression.cpp | 42 |
1 files changed, 41 insertions, 1 deletions
diff --git a/src/corelib/tools/qregularexpression.cpp b/src/corelib/tools/qregularexpression.cpp index b7a5c3de8e..17988bdb31 100644 --- a/src/corelib/tools/qregularexpression.cpp +++ b/src/corelib/tools/qregularexpression.cpp @@ -509,6 +509,22 @@ QT_BEGIN_NAMESPACE QRegExp::CaretAtOffset behaviour. There is no equivalent for the other QRegExp::CaretMode modes. + \section1 Debugging code that uses QRegularExpression + + QRegularExpression internally uses a just in time compiler (JIT) to + optimize the execution of the matching algorithm. The JIT makes extensive + usage of self-modifying code, which can lead debugging tools such as + Valgrind to crash. You must enable all checks for self-modifying code if + you want to debug programs using QRegularExpression (f.i., see Valgrind's + \c{--smc-check} command line option). The downside of enabling such checks + is that your program will run considerably slower. + + To avoid that, the JIT is disabled by default if you compile Qt in debug + mode. It is possible to override the default and enable or disable the JIT + usage (both in debug or release mode) by setting the + \c{QT_ENABLE_REGEXP_JIT} environment variable to a non-zero or zero value + respectively. + \sa QRegularExpressionMatch, QRegularExpressionMatchIterator */ @@ -972,6 +988,25 @@ void QRegularExpressionPrivate::getPatternInfo() /*! \internal */ +static bool isJitEnabled() +{ + QByteArray jitEnvironment = qgetenv("QT_ENABLE_REGEXP_JIT"); + if (!jitEnvironment.isEmpty()) { + bool ok; + int enableJit = jitEnvironment.toInt(&ok); + return ok ? (enableJit != 0) : true; + } + +#ifdef QT_DEBUG + return false; +#else + return true; +#endif +} + +/*! + \internal +*/ void QRegularExpressionPrivate::optimizePattern() { Q_ASSERT(compiledPattern); @@ -981,7 +1016,12 @@ void QRegularExpressionPrivate::optimizePattern() if (studyData || (++usedCount != OPTIMIZE_AFTER_USE_COUNT)) return; - int studyOptions = PCRE_STUDY_JIT_COMPILE; + static const bool enableJit = isJitEnabled(); + + int studyOptions = 0; + if (enableJit) + studyOptions |= PCRE_STUDY_JIT_COMPILE; + const char *err; studyData = pcre16_study(compiledPattern, studyOptions, &err); |